ajdelange wrote:This is a joke, right? A joke is fine but some less experienced readers might take it seriously.

No joke. I'm confused why you defaulted to that conclusion.

Take the situation where a brewer has a conical with short legs and needs to pump uphill to bottle on a bench. While it is not an a fortiori conclusion that a bottling operation negates the availability of CO2 it is true that an awful lot of bottlers don't have CO2 so they need to get the beer to flow up hill. Absent a peristaltic pump, the easiest way to do that is air pressure.

So no it's not a joke. In fact, it'll be part of my brewery when finished. I intend to use a foot pump to drive beer up to my bottling station.

For their benefit: The main reason for counterpressure filling of kegs or bottles is exclusion of air - in particular the oxygen in it.

I think that would be your main reason.

It may not even be a valid one. Think on it. Unless you are causing a stir with a jet of air, the CO2 over the beer will remain there and any O2 will be at the top of the tank. I don't know how much of a jet it'd take to disturb the CO2 layer, but it is not an insubstantial amount of CO2 over the beer, and probably a foot pump wouldn't produce sufficient turbulence to disturb it sufficiently to displace it no matter how one tried. Besides the inlet opening doesn't need to be configured in the form of a restriction nozzle (jet) thus no possibility for a forceful jet of air anyway.

One of the main reasons for buying a CC fermentor is so that you can do CO2 CP transfer to keg (or bottle but usually by way of a keg) and have kegs that are good for 12 months or more.

It wasn't mine.

I got a 15 gallon conical so I could ferment in one vessel and dump yeast without all the muss and fuss of a transfer.

I rather suspect that all the worry over a little O2 getting at the beer at packaging is more hype and nonsense than reality. It might be an issue for those who filter their beer to get the yeast cells out, but not everyone filters. In fact, I anticipate that the yeast that remains in the beer will clean the beer up in the bottle or keg as well as eliminate any O2 that slips in during bottling or handling.

All the things you talked about are all quite valid, but there's a larger universe of brewers than those who fit the model you describe.

Well, if you stood up in front of, for example, my brew club and made that statement all the experienced brewers would laugh. The newbies might wonder what was so funny but the experienced guys (and gals) would definitely think you were kidding.

All the things you talked about are all quite valid, but there's a larger universe of brewers than those who fit the model you describe.

I'm addressing members of that universe that want to get into the subset that makes the best beers. The ones in that subset know that they need to protect their beers from chloramine, bacteria, fats.... and oxygen.

I have a 27 gallon conical and typically fill 4 kegs out of it. I don't have legs and use my sanitized march pump to pump into the purged kegs. I purge my lines, pump and then again purge my kegs when filled. I am of the opinion that there is a CO2 layer over the beer in the fermenter so the outside air being drawn into the fermenter shouldn't come into contact with my beer. Now it may be possible for foreign objects (bugs, dust etc.) to be drawn in with the air and so I typically use a hepa filter where the air is coming in.It takes a lot of CO2 to force 20 gallons of beer out of the conical and then into the kegs. My first attempt at doing this I killed a 3/4 full 5lb tank. So I needed to find an alternative and have yet to have an issue doing it this way.What potential issues would you find from my process?

Just the one - exposure to oxygen. If you are doing British style ales it may not be an issue at all as these are traditionally served from wooden casks open to the air (through a porous spile which filters out the bugs and dirt). But they must be consumed fairly quickly. Filling 4 kegs implies that the time before all the beer is gone may be extended and here there would be danger of oxidation from 2 sources. First would be oxygen picked up by admitting air into the fermenter and second residual air in the keg. Yes, the CO2 blanket in the fermentor provides some protection but not complete as you have diffusion and mixing to some extent and it doesn't take much oxygen to ruin a beer that is under storage for an extended period.

Let's move to purging of the kegs for a minute. If you have a keg filled with air (1 atm absolute with 0.2 atm O2 i.e. 20%) and pressurize to 30 psig (3 atm absolute) with CO2 the mixture of CO2 and air will be 20%/3 = 6.7% O2 and stay at that percentage when the keg is bled down for filling. Repeating the process will reduce the O2 by a factor of 3 again but that still leaves 2.2% O2. This is more than desirable for long term storage of beer. Many homebrewers solve this problem by filling the sanitized keg absolutely full with boiled water and then pushing that water out with CO2 and then proceding with counter pressure filling, pushing the beer out of the fermenter with CO2.

Yes, it takes 20 gal of CO2 to displace 20 gal of beer in the fermenter and 20 gal of CO2 to displace the water which displaced the air in (4) 5 gallon kegs but that's the price you must pay for very low oxygen pickup. As you should be able to serve many 15.5 gal Sankeys from (1) 5 pound CO2 bottle it shouldn't take 3 - 4 lbs of CO2 to displace 20 gal which is about 1 -1/3 Sankeys. And you should be able to get CO2 for less than a buck a pound (50 lb siphon bottle).

Whether this is worth it or not to you is something that you must decide for yourself and the best way to do that would be, IMO, to go through the whole 9 yards of counter pressure filling, water displacement etc. with a delicate lager and then use the method you described for another batch. If the CP beer doesn't taste that much better WRT to oxidation, staling, diacetyl... at the end of the storage period then clearly the added trouble and expense isn't worth it.

I am able to keep kegged beer fresh for a year or more by using the CP procedure but I also make sure some live yeast goes into every keg and every keg sits in a cooler undisturbed until it is finished and those both contribute to the long term stability.

Last edited by ajdelange on Thu Jan 26, 2012 11:37 am, edited 1 time in total.

ajdelange wrote:If you have a keg filled with air (1 atm absolute with 0.2 atm O2) and pressurize to 30 psig (3 atm absolute) with CO2 the mixture of CO2 and air will be 20/3 = 6.7% O2 and stay at that percentage when the keg is bled down for filling.

I had to read that about 5 times before I figured out you meant 0.2/3 (20%/3) . I think I need more coffee this morning

ajdelange wrote: One of the main reasons for buying a CC fermentor is so that you can do CO2 CP transfer to keg (or bottle but usually by way of a keg) and have kegs that are good for 12 months or more.

Well my main reason for going with a conical was the ability to drop trub and collect yeast for reuse, without the pick up of oxygen that you have with buckets or carboys. The 2-stage temp controller and ability to conduct a closed transfer clinched it for the More Beer conical.

AJ, in terms of the flavor in the finished beer both initially (say a month out) and looking more longitudinally, how would a closed transfer from fermenter to keg compare with gravity feeding and simply purging keg and transfer tubing with CO2?

I did not bother with a closed transfer with my first batch, a sweet stout which tasted pretty awesome. It's in my chest freezer now around 37F. I believe that it should be fairly stable. Do you agree?

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